Coach and teacher Craig Kemp said the school qualified to send two teams - the School Boyz and the Mixed Team - after sending a video recording of them performing in Dunedin recently.
It was the fourth year in a row the school had qualified, but this was the first time the school had qualified to send two teams to the event.
It was also the first time an all-boys team from the school had qualified, he said.
Grants Braes was the only school south of Christchurch to qualify.
"We're thrilled. It's absolutely fantastic. I'm particularly delighted with the boys' team.
"Historically, dancing hasn't been seen to be something cool for boys. They are more into rough-and-tumble sports.
"But these boys don't care what other people think of them. They just love getting out there and giving it a go."
The School Boyz have been busy rehearsing their dance routine to Poi E, while the Mixed Team would be performing Proud Mary.
Jump Jam Kidz Aerobix is the brainchild of two-time world aerobic champion and eight-time New Zealand aerobic champion Brett Fairweather, who is committed to making exercise safe, simple, effective and fun.
The national final will be held in Auckland in November.
